||28 to 36 inches tall
||100 to 135 pounds
||Savanna and light
||Between 6 and 7 months
cheetahs, hyenas, hunting dogs
The graceful impala is a slender, medium-sized antelope so
adaptable that it is found from southern Africa to the
northern limits of East Africa.
The body is reddish-brown with white hair inside the ears,
over each eye and on the chin, upper throat, underparts and
buttocks. A narrow black line runs along the middle of the
lower back to the long tail, and a vertical black stripe
appears on the back of each thigh. Unlike other antelopes,
impalas have large, brushlike tufts of long, coarse black hair
that cover a scent gland located just above the heel on each
Impalas are found at grassland and woodland edges, usually
very close by water.
Their social organization allows impalas to adapt to
prevailing environmental conditions. When food is plentiful, the
males become territorial. In home ranges averaging 3 square
miles, six to eight dominant males set up territories. They
stand with erect posture, rub scent from face glands and make
dung heaps to mark their territory.
The females form herds of 10 to 50 or more and wander in and
out of male territories. If they start to leave the territory,
the male tries to herd them back to the center, or he feigns
danger just beyond his boundary by taking a stance normally used
as a warning sign. He tries to mate with females in estrus and
defends his territory from challenging males. Bachelor males are
allowed to remain in male territories if they ignore the
The territorial male's challenger will have worked his way up
through the hierarchy of the bachelor group until he becomes the
dominant male. He then leaves the group and challenges a
territorial male through horn duels, in which the males approach
one another with slow, deliberate steps. At a signal, such as
swiveling the eyeballs to show the whites or slightly nodding
the head, they rush forward and clash horns, attempting to throw
one another off balance. Although fighting can be fatal, males
are protected by exceptionally thick skin over vulnerable areas.
It is not the length of horn that gives a male the advantage but
his condition and weight. When a territorial male begins to lose
weight from his frantic activity, he is defeated and must return
to the bachelor group to recuperate. There are times, however,
when this territorial system is not maintained. In drier years
the animals have to travel further to obtain food, and many
smaller herds of females form. They move in and out of the
territories so often that the males are very quickly exhausted.
When this happens, territories are abandoned, and large, mixed
tranquil herds of females and males form. When feed conditions
improve, impalas revert to the territorial system.
Impalas eat tender young grass shoots in the wet season and
herbs and shrubs at other times. During the dry season they
must drink daily.
Caring for the Young
In East Africa young are born year round, but birth
peaks usually coincide with the rains. The female leaves the
herd and seeks a secluded spot to bear her fawn. After giving
birth she cleans the fawn and eats the afterbirth. If the fawn
is born at a time when there are few other young around, the
mother will stay with it in seclusion spot for a few days or
even leave it lying out for a week or more before returning to
the herd. If there are many other fawns, she may take hers back
to the herd in a day or two, where a nursery group may form.
Because predators have more difficulty selecting an individual
from a nursery group, the fawns are safer there.
The young are suckled for 4 to 6 months and grow rapidly,
reaching maturity at a little over a year. The young males,
however, are evicted from their mothers' groups when they are 6
months old, staying around the edges of the herd until they join
a bachelor group. During this transition period they are most
vulnerable to predators. Males will not be mature enough to hold
a territory until they are 5 or 6 years old.
The young are killed by jackals and the smaller cats, baboons,
eagles and pythons. When in danger, impalas will "explode" in
a magnificent spectacle of leaping. In their zig-zag leaps,
they often jump over and across their companions, probably to
confuse predators. They perform a high kick of the hind legs,
a movement thought to release scent from the glands on the
heels, making it easier for them to stay together.
Did you know?
- The female is similar to the male but does not have horns.
The male's graceful lyre-shaped horns are 18 to 37 inches
- During periods of intense mating the male vocalizes loudly,
making a sound between a lion's roar and a dog's bark.
Exhausted by such activity, males seldom can hold their
territories for more than a few months at a time.